Storm will plant a wet one on San Diego this Valentine's Day

An atmospheric river from the sub-tropics is going to unload on San Diego County Thursday -- Valentine's Day.

An atmospheric river from the sub-tropics is going to unload on San Diego County Thursday -- Valentine's Day.

Gary Robbins

Not to take the romance out of Valentine’s Day, but this year a sturdy umbrella might be a better gift than chocolate or flowers.

The National Weather Service says a huge, warm plume of moisture from the sub-tropics will arrive in San Diego County and drench a region that’s already squishy from earlier storms.

The system will begin spreading rain late Wednesday. But the core will hit on Thursday — Valentine’s Day — when the moisture rides up the side of local mountains, condenses, and unleashes heavy rain. Its called orographic lift.

Forecasters say Palomar Mountain could get 4 to 6 inches of rain, while Julian gets 3 to 4 inches and Ramona gets 3. San Diego and other coastal cities will be 1 to 1.5 inches of rain.

The winds will gust up to 35 mph at and near the coast, and 40 mph or higher inland, especially in the mountains along Interstate 8, east of Alpine. The combination of slashing rains and wind is expected to make interstate driving hazardous.